Okay, so I've googled this one to no avail. I've got two machines - one this works fine on, the other it doesn't. Both Vista Ultimate 32-bit. And I have it working in a Virtual PC (XP Pro) on the same machine that it won't work on natively.

I get an error when it tries to start Tivo Desktop or Tivo Server, saying "The Parameter is Incorrect".

I installed TiVo Desktop 2.5 last night on my Vista Ultimate machine and it works fine for me.

Do you have User Access Control disabled in Vista? That might cause some problems if it isn't.
The first thing I did after the Vista install was to disable UAC since it seems to be a pain allowing access when something externally needs to access the PC or the PC needs to access something on the network. It was just too many hoops to jump through to work properly.

Had the same problem last night. I did a force connect to Tivo and received some updates. After the update completed It all worked. Make sure that you check the "transfers allowed" on the tivo site in your account manager. It also states that it can take up to 24 hours to take effect. I had done this earlier in the day and I believe that the force connect to Tivo services brought the settings down because after the update a new option was added under system and messages screen that had a tag to display your media key. Wasn't their prior to the updates.

So am I. After installing the desktop software. I could transfer pictures and music down to the series 3 but everytime I tried to get the now playlist from the desktop software I got the same message "access denied" My desktop is running on Vista also.

I'm going to make a suggestion. Disconnect your PC from the network (wired and wireless) and try bringing up the Tivodesktop. The error message that you posted actual comes up when selecting "Pick recording to transfer" which actually is trying to conect to a Tivo box. If the media key is not set or is incorrect you will get the message ""Tivo server error" "access denied". If your disconnected from the network you will get the message "there are no Tivo DVR's avaliable"

Try it and see if you get the same message "Tivo server error" "access denied" or different one.

Credit to Greg Burns on another thread for posting this, but although I am STILL sitting on hold with Tivo (been on hold for over 45 minutes now as they supposedly try and fix the problem), I found the info that I'm reposting below.

Credit to Greg Burns on another thread for posting this, but although I am STILL sitting on hold with Tivo (been on hold for over 45 minutes now as they supposedly try and fix the problem), I found the info that I'm reposting below.

Changed that to be E:\My Tivo Recordings and everything started right up w/o error.

My directory is "F", but bottom line, I took out the second "\" and I'm good to go.

Thanks again to Greg.

I've had one PC running "T-Desktop" for quite a while with no problems. Today I installed to another PC and ran into the same problem as others mentioned above, even with downloading the most recent Desktop installer available. I would have spent hours running around in circles trying to identify what the problem was. Instead, did a google for : "the parameter is incorrect +tivo" and came right to this forum response. The fix was all of 30 seconds and it worked perfectly. Thanks!!

(I can't believe Tivo has not made a simple fix to the installer to correct this error. Can you imagine how many man-hours have been wasted not only by consumers in the past 6 months, but also the Tivo support staff, attempting to fix this problem? The lack of an updated installer speaks volumes about Tivo's management priorities-- obviously, quality isn't high on the list.)

Credit to Greg Burns on another thread for posting this, but although I am STILL sitting on hold with Tivo (been on hold for over 45 minutes now as they supposedly try and fix the problem), I found the info that I'm reposting below.

The registry fix worked for me. I have a screwy system, with My Documents on an H drive, as I was using one of those 10K RPM drives as a C drive, and I did not have enough room for all my stuff. I finally got aggravated about that and used Acronis True Image to replace my C with a 750GB. After I did that, with no other changes made by me, I got that Tivo server error. I changed the entry to h:/blahblahblah\My Tivo Recordings and boom, it worked.

Credit to Greg Burns on another thread for posting this, but although I am STILL sitting on hold with Tivo (been on hold for over 45 minutes now as they supposedly try and fix the problem), I found the info that I'm reposting below.

Changed that to be E:\My Tivo Recordings and everything started right up w/o error.

My directory is "F", but bottom line, I took out the second "\" and I'm good to go.

Thanks again to Greg.

Props to Greg (for posting) & ericgoldy (for reposting here) for this fix - it also worked for me. (FYI, the folder directly under HKEY_USERS consisted of some different numbers than what's posted here - may be due to a newer version of TTG? But it's pretty easy to figure out which folder is the one to go to, if your numbers differ, too.) (I have moved the My Documents location from my C drive.)

Nearly 6 and a half years after ericgoldy posted that registry edit, and it is still helping people.

I just installed a new hard drive and moved all my data from the old drive to the new. After rebooting, TiVo Desktop wouldn't run ("The Parameter is Incorrect"). There was no option to uninstall it and running the installation script failed.